If it requires suffering to sing the blues then there is a definite credibility about the Blues Brothers show that hits St David's Hall, Cardiff, tomorrow night.

The wordily-titled Jake and Elwood in The Best Blues Brothers Show in the World - Ever! (there's a reason for that) stakes its claim at authenticity, riffing on both the 1980 smash hit film and the actual live act that preceded it.

This live tribute, which started in 1988, is performed by the artists formerly known as William Smith-Eccles and Mark John Moore but a quick deed poll switch means they are now officially Joliet Jake Blues and Elwood J Blues, respectively (check their passports).

'A lot of people don't realise that the Blues Brothers were a real live gigging band,' said Elwood/Moore, a deadpan Scouser out of character.

'They started in 1976 before the film and it was Dan Aykroyd and John Belushi who fronted it so what we try to do is recreate all that live stuff.

'Everything is live and we always stress that because there are a lot of bands out there who do this by miming.'

That hints at some of the bitter experience Eccles and Moore hold over a spat they endured with the West End version of the show that stomped on their turf in the '90s.

'We were asked by them if we didn't mind using the words 'official tribute' by the West End show and stupidly I said I don't mind - I'm not a businessman,' said Eccles/Jake, who at a grizzled 56 has learned some harsh lessons about life on the road.

'About five years back, before I met a businessman who organised the show for me, I went #126,000 in debt keeping this 12-piece band together,' he said with something resembling pride.

'I had bailiffs coming so regularly we were on first-name terms.

'It cost me my marriage too, my wife left me through it.'

Does he regret dedicating his life to the show?

'Not for one minute, although I regret splitting with my wife because I miss her.

'If I could get the buzz from doing this by doing it at home in the garage then I would but I can't.'

It is not surprising then that having put so much into the act the pair want to ensure it has been worth their while but can a tribute show get close enough to the real thing?

'Yes and no,' said Moore/Elwood.

'I studied the way Aykroyd dances and plays the harmonica and I do try to mirror image him but it's more about getting the spirit of it while playing those characters as accurately as we can.

'We like people to go away thinking that they have just seen Belushi and Aykroyd as they would be now and we get a big response to it.

'I maintain to this day that if Dan Aykroyd came to see us he would be proud.'